The long-term overall objective of the research is to advance our understanding of the immunological and functional aspects of injury induced in some human or animal tissues by antibody and by antigen-antibody complexes. The specific problems to be studied are: 1) the pathogenesis of autoimmune systemic disease induced in animals by mercury, a common agent of environmental pollution; 2) the effect of O2 in immunologically-mediated pneumonitis; 3) the cytotoxic injury induced by antibody to brush border in renal proximal convoluted tubules; 4) the morphological and functional changes induced by deposition of antigen-antibody complexes in the oocytes, the intestine and the spleen in laboratory animals. The experimental animal models necessary for these studies are already available in our laboratory. Moreover, we have the opportunity to study a large number of tissues and sera from patients with nephritides or other immunological diseases. The approaches used to investigate these problems are the same employed in the past decades for the study of the immunopathogenesis of glomerulonephritis and will involve a combination of techniques including isolation and characterization of antibody or antigen-antibody complexes, immunofluorescene, light, transmission and scanning electron microscopy, radioimmunological methods, methods for evaluation of intenstinal permeability, splenic phagocytic function and respiratory gas exchanges. We wish to study experimental models of immunologically-mediated diseases and to verify the significance of these observations in diseased man.